Panel board coating apparatus



A. W. HElNO Oct. 29, 1957 PANEL BOARD comme APPARATUS Filed Dec.

T72 vena? i772@ Z. Hein@ United States Patent O PANEL BOARD COATINGAPPARATUS Arne W. Heino, Cloquet, Minn., assignor to Wood ConversionCompany, St. Paul, Minn., a corporation of Delaware Application December21, 1953, Serial No. 399,415

7 Claims. (Cl. 118-239) The present invention relates to coating methodsand apparatus and, in particular, to coating raw beveled edges ofsurface-coated decorated panel material, such as insulation board.

Panel board for interior decorative use has long been available on themarket. Processes have been employed for coating the decorative surfaceas a part of the process of manufacturing the board, as, for example, bycoating machine-widths of the material, sometimes in the wet-mat form,in the case of insulation board, before cutting to panel lengths anddrying, and sometimes on dried panel lengths.

Fo enhance the utility of such decorative board material, it has beencut into so-called plank or tile which are, respectively, board-likelengths, or rectangular pieces. such as acoustic squares primarilyuseful on ceilings. The acoustic squares commonly have a multiplicity ofopenings inwardly from the face for sound absorption.

ln cutting plank and tile from coated machine-width panels, it has longbeen a practice to bevel the edges so that in edge-to-edge placement ina wall or ceiling there is formed by adjacent bevels a slight groovewhich is attractive to the eye, and yet functional to prevent anunsightly joint which otherwise would be formed from abutting square-cutedges.

One practical disadvantage in so cutting bevels at the edges of coatedfaces, is that the resulting exposed body is uncoated, and therefore instrong contrast in texture, and usually in color, to the coated face.The color of the exposed material in the bevel edge may attractivelyblend with the color of the coated surface when initially formed, butsuch color is not stable in the case of lignocellulose fibers. Thelatter change in color on exposure to light and air assuming new colorvalues which are various mixtures of red, brown and yellow which are notattractive. Therefore, for stability of color in installed pieces oftile and plank it is most desirable that the raw beveled edges be coatedwith a stable color, and prefereably with a color which is of the samecomposition as that of the coated face.

The present invention aims to provide method and apparatus for quicklyapplying a coating composition to the exposed surface at the beveledfaces of insulation board and other panel products.

It is an object of the invention to provide apparatus which limitsapplication of the coating composition to the beveled faces, withoutspill-over or smear on the face of the panel.

It is also an object of the invention to provide apparatus which may beused in a continuous line of production.

It is a particular object of the invention to provide apparatus having aplurality of coating units for coating rectangular pieces on fourperipheral beveled edges in a production line.

It is also an object to provide a coating unit having moving partssuitable for continuous operation and of 2,811,133 Patented Oct. 29,1957 rice such character that the operating unit functions to coat onlywhen material to be coated moves relatively past the unit in coatingcontact therewith.

Various other and ancillary objects and advantages of the invention willbecome apparent from the following description and explanation of thepresently preferred embodiment of the apparatus and of the manner ofusing the same, as illustrated in the accompanying drawings, in which:

Fig. 1 is a diagrammatic view of equipment containing four coating unitsas it may be used to coat the four beveled edges of acoustic squares.

Fig. 2 is a view of the heated ironing element taken on the line 2 2 ofFig. 1 crossing the path of the tile and showing the tile incross-section.

Fig. 3 represents in front elevation and partial crosssection on line 33 of Fig. l the general arrangement of a smoothing unit and a coatingunit in contact with beveled edge unit of insulation board.

Fig. 4 is a view of the pick-up disk taken on line 4-4 of Fig. 3, thedisk being partly broken to show the underlying structure.

Fig. 5 is a view partly in cross-section in a vertical plane through theaxis of the transfer roll showing its contact with the portion beingcoated and its relation to the disk.

Fig. 6 is an enlarged detail view in cross-section showing the relationof drying lamps to the coated edge.

Insulation fiberboard is porous, and cross-cut surfaces of it have loosefibers and fiber ends which give the cut edge a velvety texturediliicult to coat for yielding a smooth coated surface. The face ofinsulation board as ordinarily formed has a diilerent texture and coatsmore smoothly than such a cut face. Where a coated cut face is desiredto be smooth, this may be accomplished first by moistening or wettingthe cut face and ironing the fibers into a smooth ilat face prior toapplying a coating composition. By spraying on water or by projectingsteam onto the cut face and then ironing it under pressure with a smoothhot metal surface, the cut face may be suitably smoothed so that onapplication of a coating composition the resulting coated face issmooth.

Accordingly, in the apparatus for the present invention there isprovided means for moistening or steaming the cut face to be coated, andmeans for ironing the moistened face, preferably by moving the articlepast and in contact with stationary elements including a hot smoothingiron. Where two parallel edges are coated simultaneously, two suchironing stations are provided, and a conveyer moves the board past thesame.

Where the coating compositions to be employed are aqueous, it is notnecessary to dry the ironed surface, and it may desirably be moist fromthe residue of water used in the ironing step. The face to be coated isthen moved past a coating unit including contact with a rotating coatingroll or disk having a cylindrical face which carries a ilm of coatingcomposition. The thickness of the lm of composition on the coating rollis predetermined so that on contact with a passing piece of board theproper amount of composition is applied with avoidance of excess. Thecharacter of the composition, the character of the board, the speed ofrotation of the roll, and the speed of travel of board, are all factors,among others, in determining the thickness of the film.

To accomplish these and other objectives, the coating unit has beenespecially devised so that adjustments may be made for accommodating itsoperation to changing conditions.

In the preferred embodiment, the machine assembly is designed forcoating the four bevel edges of acoustic squares, and it has twosubstantially duplicating sections at right angles to each other asappears in Fig. 1. There is a stacker for a pile of squares T andbeneath it two conveyer chains 11 running over pulleys 12 on drivingaxle 13. The chains have lugs 14 located to slide one tile T from thebottom of the stacker, and spaced to provide a succession of tiles Talong leg 16 of the machine and to discharge them into a second stacker17. A similar leg 18 of the machine lies at right angles to leg 17, butat a lower level, and it has conveyer chains 19 to remove the bottomtile from stacker 17, for processing in the same manner as will bedescribed with respect to leg 16. One leg processes one set of opposingbevels, and the other leg the other set. Only one leg will be describedin detail.

The processing as described for aqueous coating compositions involvesthe sequence of ironing, coating and drying. The ironing may be precededby applying a jet of steam or a spray of water on the bevel surface, butthis is not always necessary. The moisture content and composition ofthe tile body may permit ironing without such a preconditioning. Thenumerals 21 indicate nozzles for such jets.

The ironing region along leg 16 is designated 22 in Fig. l, and indetail is illustrated in Fig. 2. Tile T has a fiber body 23, a finishingcoat 24 over its top face, a grooved edge 25 to match a tongued edge onthe opposite side (not shown), and a raw bevel face or edge 26 to becoated. Numeral 27 indicates an electrically heated unit to which isremovably secured an ironing element 28 of form to iron bevel face 26. Alike unit functions on the opposite bevel. The irons 28 are adjusted tomatch the dimensions of the tile T, which are uniformly sized with aminimum of tolerance for use in ceilings. The ironing units may beresiliently mounted for uniformly pressing tiles of non-uniformdimensions within a prescribed tolerance.

The coating region along leg 16 is designated 33 in Fig. l and isillustrated in details in Figs. 3 and 4. In general, it involves meansfor providing a supply of composition for forming a film on a rotatingpick-up element, doctoring means to function on the pick-up element forlimiting the supply available for a transfer roll which applies thecomposition to the bevel face.

The composition is first applied in excess to the pick-up element, as bya running stream or a pool, such as the liquid 34 of permissiblyvariable depth in open receptacle 3S. A rotating pick-up element has aface on which the composition is applied in excess of actualrequirements. The preferred element is a disk 36 having its edge dippinginto liquid to wet the peripheral zone of its flat face 37. The face 37is shown parallel to the bevel face 26 to be coated. The disk is rigidon shaft 38 and driven by gears 39 from power shaft 40 parallel to bevelface 26. Driving pulley 41 on shaft 40 is connected by belt 42 to adrive shaft (not shown) common to the duplicating coating unit on theopposite side. The speed of rotation of the disk 37 is such that theiilm of composition picked up by it is not centrifugally discharged, forexample, about 95 R. P. M. when the disk diameter is about 7 inches.

As a reference region of the disk face 37 leaves pool 34 it approachesdoctoring means effective by its adjustment to pass a predeterminedamount of the composition and to hold back and strip off the excess. Theretained composition is in the form of a film of controlled thickness.The doctoring means may be a knife blade, but a roller has been foundmore satisfactory and is preferred for the reason that rotation of adoctoring roll effects removal of any undesired particles whichotherwise would collect against a stationary doctor.

The preferred doctoring means is a medium hard resilient rubber roll 45,idling on shaft 46 and driven by disk 36 as a result of slight pressurethereon. The pressure regulates the amount of film on disk 36 passingthe doctor. The area of contact on the disk 36 may be anywhere from theedge inwardly and the location and width Cil are such that thehereinafter mentioned transfer rcll has its active face lying in thefilm predetermined by the doctor. As illustrated, the doctoring roll isat the edge of the pick-up face 37.

In Fig. 4, the preferred relations of the pick-up disk 36, the doctoringroll, and a transfer roll 5G are illustrated in the plane of the diskface 37. The dotted region 5l on the periphery of the doctor roll 45represents the area of pressure contact between it and the disk face 37.The region indicated by arrow 52 between the periphery of disk 36 andthe inner dotted line represents the width of the film formed by thedoctor roll 45 for presentation to the transfer roll 50. The latter hasa fixed axle 53 parallel with bevel face 26 (see Fig. 3) with drivenpulley 54 connected by driving belt 55 to pulley S6 on the drive shaft40.

The transfer roll has a cylindrical face which takes coating compositionfrom the controlled film on the pickup disk and which applies it bycontact with the bevel face 26 moving past it in tangential contact. Thetransfer disk rotates at a peripheral speed sufficiently low to preventcentrifugal discharge of the coating composition, for example, about 166R. P. M. for a diameter of about 2 inches. As arranged and preferablyoperated, the transfer roll runs against the pick-up disk and henceagainst the direction of movement of the tile T. The transfer roll isgenerally cylindrical in character, and may have circumferential groovesor other depressions for increasing holding capacity for liquid. Suchdepressions are so formed that in the sliding of the tile past thetransfer roll, the bevel face is not roughened or altered. A cylindricalgroove is an example, as shown in Fig. 5, wherein transfer roll 57 has acylindrical face S8 and a peripheral groove 59 in said face. Thetransfer roll 50 lacks such a groove.

Whether or not the transfer roll touches the disk 36 or is spaced fromit depends on the structure of the transfer roll, the character of thecomposition, the character of the tile body, and other adjustments. Thesmooth transfer roll 50 preferably operates at a clearance in the rangefrom .002 to .005 inch, to pick up a suliicient quantity for adequatetransfer. When the transfer roll is grooved, as is roll 57, theclearance may be reduced to substantial contact.

The width of the face of the transfer roll is at least as wide as thebevel face 26 to be coated, and preferably slightly wider, when thecoating composition for the bevel is the same as forms the coat 24 onthe tile face. When it is so wide, there is assurance of completecoating of the bevel face, and incidentally a slight spill-overespecially onto the face coat 24. In such case, air jets (not shown)operate to blow the excess away.

The drying region along leg 16 is designated 60 in Fig. l and in detailis illustrated in Fig. 6. On the tile T the numeral 61 indicates thecoating composition applied to the bevel face 26 by a transfer roll,such as 50 or 57. Along a portion of the length of leg 16 over the pathof each bevel face is a drier. A suitable one has a source 62 of infrared light, a reflector 63, a housing 64, and deliectors 65, thusdirecting the heat toward the wet coat 61 to dry it rapidly by the timeit reaches the end of leg 16. Then the conveyer chain 11 delivers thetile T to stacker 17, from which it is taken in a right angulardirection by conveyer chains 19 for repeating the procedure on theremaining two bevels.

Although the apparatus illustrated is adjusted for square units, it isto be understood that the components may be placed in differentpositions adapting the apparatus for oblong units. Various othermodifications in the apparatus and method are contemplated as fallingwithin the scope of the present invention as expressed in the appendedclaims.

I claim:

l. Apparatus for coating comprising a rotary pick-up disk, means forpresenting to a face of said disk a supply of liquid coatingcomposition, said disk being arranged for rotation at a fixed speed suchas to hold a film of said liquid on said face against centrifugaldischarge, doctoring means positioned adjacent the said face of the diskin relation to reduce and control the thickness of film on the pick-updisk in the region beyond the doctoring means, a rotary transfer rollhaving a peripheral cylindrical face arranged to rotate with its saidface substantially parallel to but spaced from the said face of thepick-up disk and lying in said film of reduced thickness, positive powermeans to rotate said transfer roll at a speed fixed relatively to thespeed of the pick-up disk yet insufficient to effect centrifugaldischarge of the uid composition from its said cylindrical face, andmeans to effect movement of a body tangentially along the cylindricalface of the transfer roll, whereby to transfer uid composition from itssaid cylindrical face to said body as a band of width not greater thanthe width of the cylindrical face of the transfer roll.

2. Apparatus for coating comprising a rotary pick-up disk, means forpresenting to a face of said disk a supply of liquid coatingcomposition, said disk being arranged for rotation at a fixed speed suchas to hold a film of said liquid on said face against centrifugaldischarge, doctoring means positioned adjacent the said face of the diskin relation to reduce and control the thickness of film on the pick-updisk in the region beyond the doctoring means, a rotary transfer rollhaving a peripheral cylindrical face arranged to rotate with its saidface substantially parallel to but spaced from the said face of thepick-up disk and lying in said film of reduced thickness, positive powermeans to rotate said transfer roll in a direction against the rotationof the pick-up disk, the speed of rotation being fixed relatively to thespeed of the pick-up disk and being insufficient to effect centrifugaldischarge of the fiuid composition from its said cylindrical face, andmeans to effect movement of a body tangentially along the cylindricalface of the transfer roll, whereby to transfer fluid composition fromits said cylindrical face to said body as a band of width not greaterthan the width of the cylindrical face of the transfer roll.

3. Apparatus for coating comprising a rotary pick-up disk, means forpresenting to a face of said disk a supply of liquid coatingcomposition, said disk being arranged for rotation at a fixed speed suchas to hold a film of said liquid on said face against centrifugaldischarge, a rotary doctoring roll having a peripheral cylindrical faceof resilient material positioned with predetermined pressure on saidface of the disk whereby to effect rotation of said roll and to reduceand control the thickness of film on the pick-up disk in the regionbeyond the doctoring roll, the speed of the doctoring roll beinginsufficient to effect centrifugal discharge of uid from its doctoringface, a rotary transfer roll having a peripheral cylindrical facearranged to rotate With its said face substantially parallel to butspaced from the said face of the pick-up disk and lying in said film ofreduced thickness, means to rotate said transfer roll at a speed fixedrelatively to the speed of the pick-up disk yet insufficient to effectcentrifugal discharge of the fiuid composition from its said cylindricalface, and means to effect movement of a body tangentially along thecylindrical face of the transfer roll, whereby to transfer uidcomposition from its said cylindrical face to said body as a band ofwidth not greater than the width of the cylindrical face of the transferroll,

4. Apparatus for coating comprising a rotary pick-up disk, means forpresenting to a face of said disk a supply of liquid coatingcomposition, said disk being arranged for rotation at a fixed speed suchas to hold a film of said liquid on said face against centrifugaldischarge, a rotary doctoring roll having a peripheral cylindrical faceof resilient material positioned with predetermined pressure on saidface of the disk whereby to effect rotation of said roll and to reduceand control the thickness of film on the pick-up disk in the regionbeyond the doctoring roll, the speed of the doctoring roll beinginsufficient to effect centrifugal discharge of Huid from its doctoringface, a rotary transfer roll having a peripheral cylindrical facearranged to rotate with its said face substantially tangential to butspaced from the said surface of the pick-up disk and lying in said filmof reduced thickness, means to rotate said transfer roll in a directionagainst the rotation of the pick-up disk, the speed of rotation beingfixed relatively to the speed of the pick-up disk and being insufficientto effect centrifugal discharge of the fiuid composition from its saidcylindrical face, and means to effect movement of a body tangentiallyalong the cylindrical face of the transfer roll, whereby to transfer uidcomposition from its said cylindrical face to said body as a band ofwidth not greater than the width of the cylindrical face of the transferroll.

5. Apparatus for coating comprising a rotary pick-up disk, means forpresenting to a face of said disk a supply of liquid coatingcomposition, said disk being arranged for rotation at a fixed speed suchas to hold a film of said liquid on said face against centrifugaldischarge, doctoring means positioned adjacent the said face of the diskin relation to reduce and control the thickness of film on the pick-updisk in the region beyond the doctoring means, a rotary transfer rollhaving a peripheral cylindrical face arranged to rotate with its saidsurface substantially tangential to but spaced from the said face of thepick-up disk and lying in said film of reduced thickness, positive powermeans to rotate said transfer roll and said pick-up disk at fixedrelative speeds, the speed of rotation of the transfer roll beinginsufficient to effect centrifugal discharge of the fiuid compositionfrom its said cylindrical face, and means to effect movement of a bodytangentially along the cylindrical face of the transfer roll, whereby totransfer fiuid composition from its said cylindrical face to said bodyas a band of width not greater than the width of the cylindrical face ofthe transfer roll.

6. Apparatus for coating comprising a rotary pick-up disk, means forpresenting to a face of said disk a supply of liquid coatingcomposition, said disk being arranged for rotation at a fixed speed suchas to hold a film of said liquid on said face against centrifugaldischarge, a rotary doctoring roll having a peripheral cylindrical faceof re- '5 silient material positioned with predetermined pressure onsaid face of the disk whereby to effect rotation of said roll and toreduce and control the thickness of film on the pick-up disk in theregion beyond the doctoring roll, the speed of the doctoring roll beinginsufficient to effect 1 centrifugal discharge of fluid from itsdoctoring face, a

rotary transfer roll having a peripheral cylindrical face arranged torotate with its said face substantially tangential to but spaced fromthe said surface of the pick-up disk and lying in said film of reducedthickness, means to rotate said transfer roll and said pick-up disk atfixed relative speeds, the speed of rotation of the transfer roll beinginsufficient to effect contrifugal discharge of the fiuid compositionfrom its said cylindrical face, and means to effect movement of a bodytangentially along the cylindrical face of the transfer roll, whereby totransfer fluid composition from its said cylindrical face to said bodyas a band of width not greater than the width of the cylindrical face ofthe transfer roll.

7. Apparatus for coating comprising a rotary pick-up element, means forpresenting to a rotating surface of said element a supply of liquidcoating composition, said element being arranged for rotation at a fixedspeed such as to hold a film of said liquid on said surface againstcentrifugal discharge, doctoring means positioned adjacent the said faceof the element in relation to reduce and control the thickness of filmon the pick-up element in the region beyond the doctoring means, arotary transfer roll having a peripheral cylindrical face arranged torotate with its said surface substantially tangential to but spaced fromthe said face of the pick-up element and lying in said film of reducedthickness, positive power means to rotate said transfer roll at a speedof rotation xed relatively to the speed of the pick-up element yetinsuclent to elect centrifugal discharge of the uid composition from itssaid cylindrical face, and means to effect movement of a bodytangentially along the cylindrical face of the transfer roll, whereby totransfer fluid composition from its said cylindrical face to said bodyas a band of width not greater than the width of the cylindrical face ofthe 10 transfer roll.

References Cited in the file of this patent UNITED STATES PATENTSPatcher July 23, Kramer Jan. 19, Baldwin July 11, Warren June 13,Bergstein Mar. 31,

FOREIGN PATENTS France July 26,

